Composite repair method

Abstract

A method of repairing a composite structure or forming a component of a part is provided. The method includes releasably laying up of a first member that is curable at a first temperature at or above a constrained temperature limit of the composite structure or part, releasably laying up of a second member on the first member that is curable at a second temperature below the constrained temperature limit, curing the second member into a scaffold at the second temperature at the composite structure or part, transferring the first member and the scaffold remotely from the composite structure or part for first member curing and removing the cured first member from the scaffold for bonding of the cured first member to the composite structure or part.

1 . A method of repairing a composite structure or forming a component of a part, the method comprising:
 releasably laying up of a first member that is curable at a first temperature at or above a constrained temperature limit of the composite structure or part;   releasably laying up of a second member on the first member that is curable at a second temperature below the constrained temperature limit;   curing the second member into a scaffold at the second temperature at the composite structure or part;   transferring the first member and the scaffold remotely from the composite structure or part for first member curing; and   removing the cured first member from the scaffold for bonding of the cured first member to the composite structure or part.   
     
     
         2 . The method according to  claim 1 , wherein the composite structure or part is contoured. 
     
     
         3 . The method according to  claim 1 , wherein the method further comprises disposing release plies on either side of the first member. 
     
     
         4 . The method according to  claim 1 , wherein the second temperature is substantially lower than both the first temperature and the constrained temperature limit. 
     
     
         5 . The method according to  claim 1 , wherein the second temperature is room temperature. 
     
     
         6 . The method according to  claim 1 , further comprising curing the first member at about 250° F.-350° F. or more. 
     
     
         7 . The method according to  claim 1 , further comprising envelope vacuum bagging of the first member and the scaffold. 
     
     
         8 . The method according to  claim 1 , further comprising:
 bonding of the cured first member to the composite structure or part using room or elevated temperature curable adhesive; and   curing the adhesive at room or elevated temperature.   
     
     
         9 . A prepreg patch and scaffold assembly, comprising:
 an autoclave or oven temperature curable prepreg patch having a contour that mimics a contour of a contoured composite structure or part; and   a scaffold formed of releasably laid up room temperature curable wet layup, the wet layup being:   releasably laid up on the prepreg patch in an uncured form to assume a contour that mimics the contour of the prepreg patch, and   cured at a temperature that is lower than a curing temperature of the prepreg patch.   
     
     
         10 . The assembly according to  claim 9 , further comprising release plies respectively disposed on either side of the prepreg patch. 
     
     
         11 . The assembly according to  claim 9 , wherein the wet layup is curable at a temperature that is substantially lower than both a curing temperature of the prepreg patch and a constrained temperature limit of the composite structure or part. 
     
     
         12 . The assembly according to  claim 9 , wherein the wet layup is heat or ultraviolet (UV) curable at room temperature. 
     
     
         13 . The assembly according to  claim 9 , wherein the prepreg patch is curable at about 250° F.-350° F. or more. 
     
     
         14 . The assembly according to  claim 9 , further comprising an envelope vacuum bag to bag the prepreg patch and the scaffold. 
     
     
         15 . The assembly according to  claim 9 , further comprising a room temperature or elevated temperature curable adhesive to bond the prepreg patch to the composite structure.